Techniques for reducing an exposed dose of an object while attempting to improve an image quality have conventionally been developed. For example, in Patent Document 1, a beam hardening error of obtained projection data is subjected to a correction process according to a scanning method, and a plurality of irradiator current values are created, which are then applied to a scanning system according to a scanning subject. It is thereby possible to reduce a dose received by individual objects and also enhance a dose efficiency regardless of sizes of the objects, while holding a low noise level to an allowable extent and favorable CNR.
Patent Document 1: Japanese Patent Laid-Open No. 2004-73865
Image quality of an X-ray CT image is largely involved in visual inspection, by a doctor, of a seat of disease in a tissue of an object or the like. To obtain better image quality, scanning condition can be set in view of absorption or transmission of X-rays specific to and different among each tissue of an object. However, in Patent Document 1, consideration is not given to setting of a scanning condition in view of absorption or transmission of X-rays specific to and different among each tissue of an object.